Photonic chips can include optical interfaces to permit optical signals to be received from an optical source (e.g., a laser or an optical fiber) or transmitted to an optical fiber or detector. Some photonic chips include grating couplers disposed at the top of the photonic chip. However, grating couplers are complicated to manufacture (e.g., may require gray scale lithography) and take up significant amount of space on the photonic wafer.
Edge couplers can be disposed at the sides of the photonic chip and are easier to manufacture and provide better optical coupling than grating devices. However, when a wafer is being processed, the edge couplers are typically inaccessible until the wafer is diced to separate the wafer into a plurality of photonic chips. As such, the edge couplers cannot be coupled to optical probes in order to test the optical components in the wafer until the wafer has been separated into individual photonic chips.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.